Ichiro Takajo

Engraftment of peripheral blood mononuclear cells from human T-lymphotropic virus Type 1 carriers in NOD/SCID/γcnull (NOG) mice

The transmission of human T‐lymphotropic virus Type 1 (HTLV‐1) occurs mainly via breast‐feeding, sexual intercourse and blood transfusions. After transmission, the HTLV‐1 infection is predominantly maintained by cell‐to‐cell infection and clonal expansion; however, the details have not yet been clarified. To investigate how HTLV‐1 infected cells act in an environment without an effective immune reaction, peripheral blood mononuclear cells (PBMCs) from asymptomatic HTLV‐1 carriers were inoculated into nonobese diabetic/severe combined immunodeficient (NOD/SCID)/γcnull (NOG) mice, which have immunological dysfunctions of T‐ and B‐lymphocytes and NK cells. Human mononuclear cells including both CD4+ and CD8+ T cells were found to have infiltrated into various organs, including the liver, kidney, spleen and lung, when the mice were sacrificed 1 month after inoculation. The copy numbers of HTLV‐1 provirus detected in the tissue‐infiltrating human cells were much higher than those in the original PBMCs from the carriers. The expression of HTLV‐1 mRNA was demonstrated in the tissue‐infiltrating cells by reverse transcriptase‐polymerase chain reaction. Inverse‐long polymerase chain reaction showed that the pattern of HTLV‐1 proviral integration was different from that of the original carrier and that it varied among NOG mice inoculated with PBMCs from the same carrier. These results suggest the selective proliferation of particular clones of HTLV‐1 infected cells in NOG mice. Alternatively, transmission and new integration of HTLV‐1 from infected cells to noninfected cells might have occurred in an environment without an effective immune reaction. The NOG mouse is considered a good animal model for the patho‐physiological study of HTLV‐1 infection with immunodeficiency.

Leukocytapheresis (LCAP) decreases the level of platelet-derived microparticles (MPs) and increases the level of granulocytes-derived MPs: a possible connection with the effect of LCAP on rheumatoid arthritis.

Microparticles (MPs) are believed to play an important role in inflammatory diseases such as rheumatoid arthritis (RA). Leukocytapheresis (LCAP) is one of the options available for the treatment of RA. We analyzed the levels of MPs in RA, by flow cytometry, especially in relation to the effect of LCAP. Twenty female patients with RA were recruited into this study. Six of the 20 patients with RA further received LCAP. Plasma levels of platelet-derived MPs were high in patients with RA and are correlated with disease activity. LCAP significantly improved RA in all six patients. The numbers of platelet-derived MPs significantly decreased after the first session of LCAP, which was probably due to direct removal by LCAP. Mean numbers of platelet-derived MPs after four sessions of LCAP markedly decreased. The numbers of granulocyte-derived MPs, which are suggested to have an anti-inflammatory effect, were markedly increased after the first session of LCAP. These data suggest that removal of platelet-derived MPs and increase of granulocyte-derived MPs are novel mechanisms of LCAP as effective treatment in RA.

Proviral loads of human T-lymphotropic virus Type 1 in asymptomatic carriers with different infection routes

High human T‐lymphotropic virus Type 1 (HTLV‐1) proviral DNA load (PVL) has been reported to be one risk factor for the development of adult T‐cell leukemia/lymphoma (ATL). ATL is also believed to develop in HTLV‐1 carriers who acquire infection perinatally. ATL cells have been reported to frequently harbor defective provirus. In our study, PVLs for three different regions of HTLV‐1 provirus (5′LTR‐gag, gag and pX) were measured in 309 asymptomatic carriers with different infection routes. PVLs for the pX region in 21 asymptomatic carriers with maternal infection was significantly higher than in 24 carriers with spousal infection. Among 161 carriers with relatively high pX PVLs (equal to or greater than 1 copy per 100 peripheral blood mononuclear cells), 26 carriers (16%) had low gag PVL/pX PVL (less than 0.5) and four (2%) had low 5′LTR‐gag PVL/pX PVL (less than 0.5). Low gag PVL/pX PVL ratio, which reflects deficiency and/or polymorphism of HTLV‐1 proviral DNA sequences for the gag region, was also associated with maternal infection. These data suggest that HTLV‐1 carriers with maternal infection tend to have high PVLs, which may be related to provirus with deficiency and/or the polymorphism of proviral DNA sequences. In addition, there is a possibility that this ratio may be used as a tool to differentiate the infection routes of asymptomatic HTLV‐1 carriers, which supports the need for a large scale study.

Use of anti-tumor necrosis factor biologics in the treatment of rheumatoid arthritis does not change human T-lymphotropic virus type 1 markers: a case series

Abstract Anti-tumor necrosis factor (anti-TNF) biologics are effective in the treatment of rheumatoid arthritis (RA); however, it is still not clear whether this treatment promotes the development of malignancies such as lymphoma. Human T-lymphotropic virus type 1 (HTLV-1), which is a causative agent of adult T-cell lymphoma (ATL), is prevalent in Japan. Many HTLV-1-positive patients with RA are assumed to exist; however, there have thus far been no reports on the effect of anti-TNF biologics on HTLV-1-positive patients. We analyzed the response to treatment with anti-TNF biologics and change of HTLV-1 markers in two cases of RA. The two cases showed no response based on the European League Against of Rheumatism response criteria 60–96 weeks after administration of anti-TNF biologics (infliximab and etanercept). No signs of ATL were observed and HTLV-1 markers, such as proviral load and clonality of HTLV-1-infected cells, showed no significant change in either of two cases. Therefore, treatment with anti-TNF biologics did not induce activation of HTLV-1, although the effect on RA was not as effective as in HTLV-1-negative patients in this limited study. Further long-term study with a greater number of patients is necessary to clarify the safety and efficacy of anti-TNF biologics in HTLV-1-positive patients with RA.

The pathogenic potential of Helicobacter cinaedi isolated from non-human sources: adherence, invasion and translocation ability in polarized intestinal epithelial Caco-2 cells in vitro

Helicobacter cinaedi infection has been recognized as an increasingly important emerging disease in humans. Infection with H. cinaedi causes bacteremia, cellulitis and enteritis. H. cinaedi has been isolated from non-human sources, including dogs, cats and rodents; however, it remains unclear whether animal strains are pathogenic in humans and as zoonotic pathogens. In this study, H. cinaedi isolates were recovered from a dog and a hamster, and the ability of these isolates to adhere to, invade and translocate across polarized human intestinal epithelial Caco-2 cells was examined in vitro. To better understand the pathogenic potential of animal H. cinaedi isolates, these results were compared with those for a human strain that was isolated from a patient with bacteremia. The animal and human strains adhered to and invaded Caco-2 cells, but to a lesser degree than the C. jejuni 81–176 strain, which was used as a control. The integrity of tight junctions was monitored by measuring transepithelial electrical resistance (TER) with a membrane insert system. The TER values for all H. cinaedi strains did not change during the experimental periods compared with those of the controls; however, translocation of H. cinaedi from the apical side to the basolateral side was confirmed by cultivation and H. cinaedi-specific PCR, suggesting that the H. cinaedi strains translocated by transcellular route. This study demonstrated that H. cinaedi strains of animal origin might have a pathogenic potential in human epithelial cells as observed in a translocation assay in vitro with a human isolate.

Treatment with anti–tumor necrosis factor biologic agents in human T lymphotropic virus type I–positive patients with rheumatoid arthritis.

To investigate the response to and safety of anti–tumor necrosis factor (anti‐TNF) therapy in human T lymphotropic virus type I (HTLV‐I)–positive patients with rheumatoid arthritis (RA).

Severe fever with thrombocytopenia syndrome with myocardial dysfunction and encephalopathy: A case report

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease in China, Korea and Japan caused by a novel bunyavirus, SFTS virus (SFTSV). Although central nervous system manifestations are common in SFTS patients, the pathogenesis has not been elucidated; and there are few reports of myocardial dysfunction. Here we report an elderly Japanese patient with reversible myocardial dysfunction and encephalopathy. A previously healthy 65-year-old male engaged in forestry got a tick bite and developed fever and fatigue in 3 days. Three days after onset, he presented to a local hospital where the diagnosis of SFTS with hemophagocytotic syndrome was made. The blood test showed leukopenia and thrombocytopenia as well as elevated levels of alanine aminotransferase and aspartate aminotransferase. Marked hemophagocytosis was found on bone marrow smear. Peripheral blood was positive for SFTSV gene by reverse-transcription polymerase chain reaction. On day 7, the patient was transferred to our hospital. We observed disturbance of consciousness, Kernig sign and myoclonus to face and limbs. Decreased blood flow of whole cerebral cortex was detected by single photon emission computed tomography (SPECT). Chest X-ray revealed cardiomegaly and electrocardiography (ECG) showed abnormal T waves. These data suggested acute encephalopathy and myocardial dysfunction. We treated him with corticosteroid and blood transfusion, which resulted in the complete recovery of the above abnormal symptoms and laboratory data including the findings in SPECT and ECG in about a month. This case demonstrated transient myocardial dysfunction and encephalopathy can occur in addition to typical clinical manifestation of SFTS.

Defective human T‐lymphotropic virus type 1 provirus in asymptomatic carriers

Few studies have specifically examined defective provirus in asymptomatic human T‐lymphotropic virus Type 1 (HTLV‐1) carriers and its relation to proviral DNA loads (PVLs). To assess the significance of defective provirus in asymptomatic carriers, we examined PVLs in peripheral blood mononuclear cells of 208 asymptomatic HTLV‐1 carriers. The mean PVLs determined using primers for the pol region were less than that for the pX region in these carriers. Analysis of seven carriers with high PVLs for the pX region but lower PVLs for the pol region showed that four had single nucleotide polymorphisms of proviral genomes for the pol region and three had HTLV‐1‐infected cells with defective provirus. Three carriers with defective provirus showed high PVLs at their initial screens, and PVLs increased after a 10‐ to 12‐year interval in two carriers. Southern blot assay showed clonal expansion of HTLV‐1‐infected cells, and the predominant clones changed during the observation period. These data suggest that although HTLV‐1‐infected cells with defective provirus may have a growth advantage, the predominant clones of HTLV‐1‐infected cells do not always survive for many years in asymptomatic carriers.

Multiple integrations of human T-lymphotropic virus type 1 proviruses in the engrafted cells from the asymptomatic carriers in NOD/SCID/gammacnull mice.

Objectives: Successful engraftment of human T-lymphotropic virus type 1 (HTLV-1)-infected cells and a marked increase of proviral DNA loads (PVLs) in non-obese diabetic/severe combined immunodeficient (NOD/SCID)/γcnull (NOG) mice have been reported. Whether the increased PVL in transplanted mice is due to the new infection of HTLV-1 was examined. Methods: Mononuclear cells from 3 NOG mice with primary engraftment from asymptomatic HTLV-1 carriers were transplanted into a second group of NOG mice. HTLV-1 PVL, proviral integration by fluorescence in situ hybridization assay, expression of viral antigen, and T-cell clonality were analyzed. Results: The PVLs in the secondarily transplanted NOG mice were significantly higher than those of primarily transplanted NOG mice. Multiple signals of HTLV-1 proviruses in the nucleus of the infected cells were revealed by fluorescence in situ hybridization analysis. Expression of HTLV-1 tax/rex mRNA and antigen was observed. The variety of T-cell clones was limited in the transplanted NOG mice. Conclusions: Multiple proviral integrations were considered to be due to the new infection from HTLV-1-infected cells to the other cells. Only a certain fraction of T cells seemed to have selectively survived in NOG mice after engraftment.

Possible Case of Novel Spotted Fever Group Rickettsiosis in TravelerReturning to Japan from India

A 60-year-old woman experienced fever, headache, rash, and altered vision after returning to Japan from India. Testing detected elevated antibody titers to spotted fever group rickettsia; PCR on blood yielded positive results for the rickettsial outer membrane protein A gene. We isolated a unique rickettsial agent and performed a full-genome analysis.